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Table 1. Select Definitions of Commonly Used Terms in
Precision Oncology
Term Definition
NGS A technolog y that performs massively parallel DNA sequencing
to detect genomic alterations.
Pathogenic or likely
pathogenic (P/LP)
variants
Variants known or suspected to be causative of disease.
Precision oncolog y e use of molecular biomarkers to aid in the diagnosis,
prognosis, or treatment of cancer.
Somatic Mutations that only occur within somatic cells and not within
reproductive cells. In cancer, somatic mutations are found within
the tumor and not within normal, non-tumor samples. DNA
from both tumor and non-tumor sites must be sequenced to
definitively ascertain if a mutation is somatic.
erapeutically
actionable
alteration
A genomic alteration predicted to confer sensitivity or resistance
to an available therapy (FDA-approved or investigational).
ese alterations are typically functionally significant, in that
they confer a change in the property of the encoded protein that
promotes tumorigenesis but may also affect drug binding and
inhibition without affecting the activity of the protein.
Tumor mutation
burden (TMB)
A measurement of the number of somatic mutations per megabase
of DNA sequenced.
Variant allele
fraction (VAF)
e fraction of alleles sequenced within a single tumor sample
that contain the genomic alteration of interest.
(cont'd)
